화학공정 위험영향 평가기술에서의 다중요소분석기법을 이용한 사고시나리오 산정에 관한 전략

김구회,이동언,김용하,안성준,윤인섭 한국화재소방학회 2001 한국화재소방학회논문지 Vol.15 No.4

현재 전세계적으로 공장내(on-site)뿐만 아니라 공장외지역(off-site)에 대한 사고영향평가의 필요성이 대두되고 있으며, 공장외지 역에 대한 영향평가 수행후 이에 대한 적절한 비상계획을 제출하도록 하고 있고, 국내에서도 종합적위험관리체계(IRMS ; Integrated Risk Management System)를 PSM이나 SMS와 더불어 시행 준비중에 있다. 그러나 공장외지 역에 대한 위험영향 평가시 가장 먼저 결정되어야할 가상시나리오에 대한 기준이 체계적으로 마련되어 있지 않아 사용자나 분석자에 따라 평가결과가 다양하게 나오며, 또한 공정에서 발생할 수 있는 사고의 이상원을 정확하게 파악하지 못한다는 단점이 있다. 따라서 본 연구에서는 이러한 가상시나리오를 결정하는데 필요한 공정요소를 분석한 후, 분석결과에 따라 발생 가능하고, 먼저 고려되어야 할 시나리오를 산정할 수 있도록 전략을 제시하고자 한다. 분석된 공정요소들은 요소에 따른 가중치를 부여하여 위험등급을 결정한 후 등급에 따른 위험영향 평가를 수행하도록 한다. 분석의 결과는 가상시나리오의 신뢰성을 향상시킴으로써 위험영향평가가 과대평가되는 것을 방지하고, 공정의 설계나 비상계획의 수립시 효과적이고 적절한 대책마련을 유도할 수 있다. This article proposes a strategy for producing accident scenarios in quantitative risk, which is performed in process design or operation steps. Present worldwide chemical processes need offsite risk assessment as well as on-site one. Most governments in the world require industrial companies to submit the proper emergency plans through off-site risk assessment. Korea is also preparing for executing Integrated Risk Management System along with PSM and SMS. However, there have been no systematic approaches and criteria for generating virtual accident scenarios, and it made impossible to get a unified or coherent assessment resell. Without the result, causes of accidents cannot be corralled precisely, To get over these shortcomings, this study analyzed process elements and then proposed a strategy for selecting and generating the accident scenario that is most likely to happen and should be foremost considered. The analyzed process elements are ranked and risk grades determined. According to the grades, risk assessment is performed. The result of analysis enhances the reliability of the generated risk scenario, and prevents some risks from being overestimated. The result should be helpful in process design and emergency planning. Keywords : Off-site risk assessment, Risk management program, Worst case scenario, ES(Equipment Screening) Method, Accident scenario selection

Alleviating Effect of the Application of the Easily Decomposable Carbohydrate on Ammonium Toxicity in Chinese Cabbage (Brassica rapa var. chinensis)

Ku, Hyun-Hwoi,Lee, Sang-Eun Korean Society of Soil Science and Fertilizer 2015 한국토양비료학회지 Vol.48 No.5

An excess application of N fertilizer causes physiological and morphological disorder known as ammonium ($NH_4{^+}$) toxicity in Chinese cabbage and it has been to be an issue for appropriate N fertilizer management. Hence, the pot experiment was conducted in order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate on $NH_4{^+}$ toxicity in Chinese cabbage. Four levels of urea at 0, 160, 320, and $640kg\;N\;ha^{-1}$, represented as T1, T2, T3, and T4, respectively, were applied. In order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate (sucrose) at T3 and T4 where $NH_4{^+}$ toxicity had occurred, five levels of sucrose were applied to meet C/N ratios of 0, 2, 4, 6, and 10, respectively. Our results showed that the $NH_4{^+}$ toxicity was observed at T3 and T4 at 5 days after treatment (DAT). $NH_4{^+}$ toxicity contributed to decrease fresh weight, length of leaves, length of root, and number of leaves significantly (p<0.05). The application of sucrose as a source of mitigating $NH_4{^+}$ toxicity had a good performance at T3 with the alleviating effect as 73 % and reduced in $NH_4{^+}-N$ content in soil at 29 DAT. In the maximum N rate of T4, however, sucrose application recovered it as 32 % only compared to T2 even though the same C/N ratio was treated. Consequently, sucrose as the easily decomposable carbohydrate played crucial role to reduce $NH_4{^+}$ concentration in soil and finally alleviated $NH_4{^+}$ toxicity in plant.

Effect of Pig Manure Compost or Sucrose Application on Recovering Chinese Cabbage from Ammonium Toxicity

Ku, Hyun-Hwoi,Kim, Seung-Hwan 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.3

This study was carried out to evaluate the effect of application of urea and combination of urea and pig manure compost (PMC) on the occurrence of and the recovery from ammonium ($NH_4{^+}$) toxicity in Chinese cabbage. To identify $NH_4{^+}$ toxicity of the crop four levels of urea at 0, 160, 320, and $480kg\;N\;ha^{-1}$ were applied, in addition, three levels of PMC at 10, 20, and $40M/T\;ha^{-1}$ was also applied with urea $320kg\;ha^{-1}$. For recovery $NH_4{^+}$ toxicity, six levels of sucrose were treated at the amount of 0, 600, 1,200, 1,800, 2,400, and $3,000kg\;C\;ha^{-1}$ at each level of combining treatments of urea and PMC. Our results showed that $NH_4{^+}$ toxicity was occurred at every urea application of $320kg\;N\;ha^{-1}$ regardless of PMC applied to the soils because $NH_4{^+}$ contents in the soils were more than $155mg\;kg^{-1}$ which was found to be the critical level to damage crop growth at 2 days after transplanting (DAT) in this experiment, the more sucrose was applied up to $1,800kg\;C\;ha^{-1}$ for the plants damaged by ammonium toxicity occurred at $320kg\;N\;ha^{-1}$, the greater extents recover the plants from the toxicity. PMC showed the similar effect with sucrose on recovering Chinese cabbage plants from $NH_4{^+}$ toxicity at 30 DAT.

Nondestructive and Rapid Estimation of Chlorophyll Content in Rye Leaf Using Digital Camera

Hyun Hwoi Ku,Seung Hwan Kim,Kwan Soo Choi,Ho-Yong Eom,Sang-Eun Lee,Seung-Gil Yun,Tae Wan Kim 韓國作物學會 2004 Korean journal of crop science Vol.49 No.1

We have developed and tested a new method for nondestructive estimation of chlorophyll- and nitrogen-contents in rye leaf. It was found that the relation-ships among nitrogen, chlorophyll content and fresh weight were significantly positive correlated. Nitrogen and chlorophyll content were positively correlated whereas correlation coefficients among R, G, R-B and G-B on the basis of photo-numerical values were negative. We have found that R/(R-B) obtained from data of digital camera is the best criterion to estimate the chlorophyll content of leaves. The regression curves of the relation between R/(R-B) and chlorophyll content were also calculated from the data collected on cloudy days. The coefficients of determination (~textrmr2 ) were ranged from 0.33 to 0.99. In this study, the accuracy in estimating chlorophyll content from the color data of digital camera image could be improved by correcting with R, G, and B values. It is suggested that, for practical purposes, the image values estimated with sufficient accuracy using a portable digital camera can be applied for determining chlorophyll content and nitrogen status in plant leaves.

화학공정의 HAZOP 분석을 위한 전문가 시스템 개발

김구회(Ku Hwoi Kim),강인구(In Koo Kang),이병우(Byung Woo Lee),이종민(Jong Min Lee),윤인섭(En Sup Yoon) 한국가스학회 1999 한국가스학회지 Vol.3 No.1

Effect of the Application of Sucrose on Rapid Decrease of Soil Inorganic Nitrogen

Hyun-Hwoi Ku(구현회),Woo-Jin Lim(임우진),Sang-Eun Lee(이상은) 한국토양비료학회 2010 한국토양비료학회지 Vol.43 No.4

질소 비료 과용에 의한 토양 무기태 질소의 과다 축적과 그에 따른 염류 집적이 심각한 시설원예 토양의 문제점을 해결하기 위하여, C/N율이 높은 이분해성 탄수화물의 시용이 토양 무기태 질소 함량과 전기전도도 감소에 미치는 영향을 실내 실험을 통하여 검토하였다. sucrose의 처리는 토양 NH₄<SUP>+</SUP>-N 함량을 크게 감소시켰는데, 감소량은 sucrose 처리량이 많을수록 컸으며, NH₄<SUP>+</SUP>-N 함량을 최저점 (약 10 mg kg<SUP>-1</SUP> 이하)에 도달하게 할 수 있는 sucrose 처리량은 최초의 NH₄<SUP>+</SUP>-N 함량에 관계없이 C/N율로 약 10부근이었다. sucrose 처리는 토양 NH₄<SUP>+</SUP>-N 함량을 매우 빠르게 감소시켰는데, 최초 NH₄<SUP>+</SUP>-N 함량 50~250mg kg<SUP>-1</SUP>을 1/2로 감소시키는데 15~36시간이 걸렸으며, 최저점 (약 10 mg kg<SUP>-1</SUP> 이하)으로 감소시키는 데에는 36~69시간이 걸렸다. sucrose 처리는 토양 NO₃<SUP>-</SUP>-N 함량을 큰 폭으로 감소시켰는데, 감소량은 처리량이 많을수록 컸으며, sucrose 처리량이 C/N율로 10 이상인 경우에는 최초 348 mg kg<SUP>-1</SUP> 이었던 NO₃<SUP>-</SUP>-N 함량이 최저 14~21 mg kg<SUP>-1</SUP>으로 감소하였다. sucrose 처리는 토양 NO₃<SUP>-</SUP>-N 함량을 매우 빠르게 감소시켰는데, 토양 NO₃<SUP>-</SUP>-N 함량을 최저점으로 감소시키는데 걸리는 시간은 sucrose 처리량이 C/N율로 10이상인 경우에는 36~60시간이 걸렸으며, 처리량이 C/N율 5로 적었던 경우에는 3주로서 상대적으로 긴 시간이 걸렸다. sucrose 처리에 의한 토양 EC의 감소는 NO₃<SUP>-</SUP>-N 함량의 감소와 같은 양상을 보였다. 논문의 결과를 응용함에 있어서 명심해야될 사항이 있다. 설탕은 인류에게 에너지와 탄소 원 (原)을 공급하는 매우 중요한 자원이므로 특별한 경우가 아니면 토양에 시용하는 것을 피해야 한다. 토양의 염류집적을 막는 최선의 방법은 시비량을 줄이는 일이며, 염류가 집적된 후에 여러 대응방안을 강구하는 것은 사후약방문 (死後藥方文)에 불과하다. To solve the problems with excessive accumulation of soil inorganic N and resulting saline soils from overuse of nitrogen fertilizer, the effect of sucrose application on decrease of soil inorganic N content and electrical conductivity (EC) was studied. Sucrose treatment greatly reduced NH₄<SUP>+</SUP>-N content in soil. The amount of reduction was greater as the amount of sucrose treatment was increased. When NH₄<SUP>+</SUP>-N content was reached the lowest point (about 10 mg kg<SUP>-1</SUP>or lower), the C/N ratio, which determines the amount of sucrose treatment, was around 10 regardless of initial NH₄<SUP>+</SUP>-N content. For the rate of NH₄<SUP>+</SUP>-N reduction 15~36 hours was required to reduce the initial NH₄<SUP>+</SUP>-N content to half, and 36~69 hours to lower NH₄<SUP>+</SUP>-N content to the lowest point (about 10 mg kg-1or lower). In addition, sucrose treatment greatly lowered NO₃<SUP>-</SUP>-N content. In case of C/N ratio above 10, initial NO₃<SUP>-</SUP>-N content of 348 mg kg<SUP>-1</SUP> was reduced to the lowest of 14~21 mg kg<SUP>-1</SUP>. As for the rate of NO₃<SUP>-</SUP>-N reduction by sucrose treatment, it took 36~60 hours for NO₃<SUP>-</SUP>-N content to reach the lowest point for C/N ratio of 10 or higher, and it took 3 weeks, comparably longer time, for C/N ratio of 5. Lowering soil EC from sucrose treatment showed the same trend as NO₃<SUP>-</SUP>-N content. As an important energy and carbon source for humankind, sugar should not be wasted and must be carefully applied to soil. In principle, the best way of preventing salt accumulation in soil is to optimize the fertilizer input. However, when over-fertilization should be dealt with, the sucrose treatment would be a possible and effective counter-measure to reduce overdosed nitrogen sources in soil.

Alleviating Effect of the Application of the Easily Decomposable Carbohydrate on Ammonium Toxicity in Chinese Cabbage (Brassica rapa var. chinensis)

Hyun-Hwoi Ku,Sang-Eun Lee 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.5

An excess application of N fertilizer causes physiological and morphological disorder known as ammonium(NH₄<SUP>+</SUP>) toxicity in Chinese cabbage and it has been to be an issue for appropriate N fertilizer management. Hence, the pot experiment was conducted in order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate on NH₄<SUP>+</SUP> toxicity in Chinese cabbage. Four levels of urea at 0, 160, 320, and 640 kg N ha<SUP>-1</SUP>, represented as T1, T2, T3, and T4, respectively, were applied. In order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate (sucrose) at T3 and T4 where NH₄<SUP>+</SUP> toxicity had occurred, five levels of sucrose were applied to meet C/N ratios of 0, 2, 4, 6, and 10, respectively. Our results showed that the NH4+ toxicity was observed at T3 and T4 at 5 days after treatment(DAT). NH4+ toxicity contributed to decrease fresh weight, length of leaves, length of root, and number of leaves significantly (p<0.05). The application of sucrose as a source of mitigating NH₄<SUP>+</SUP> toxicity had a good performance at T3 with the alleviating effect as 73 % and reduced in NH₄<SUP>+</SUP> -N content in soil at 29 DAT. In the maximum N rate of T4, however, sucrose application recovered it as 32 % only compared to T2 even though the same C/N ratio was treated. Consequently, sucrose as the easily decomposable carbohydrate played crucial role to reduce NH₄<SUP>+</SUP> concentration in soil and finally alleviated NH₄<SUP>+</SUP> toxicity in plant.

Evaluation of Nitrogen Fertilizer Application in Rice Productivity and Ghg Emissions in Irrigated Rice Production

Hyun-Hwoi Ku(구현회) 한국토양비료학회 2015 한국토양비료학회 학술발표회 초록집 Vol.2015 No.5

Long-term Effect of Rice Straw Incorporation on Soil Organic Carbon Content in Korean Paddy Soil Simulated by DNDC Model

Hyun-Hwoi Ku(구현회),Sang-Eun Lee(이상은),Chang-Hyu Yang(양창휴),Jin-Hee Ryu(류진희) 한국토양비료학회 2015 한국토양비료학회 학술발표회 초록집 Vol.2015 No.5

Comparison of Different Approaches on Determining Nitrogen Balance in a Lowland Paddy Soil

Hyun-Hwoi Ku 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.3

Nitrogen (N) balance is a key indicator assessing a degree of soil fertility and N loading by accounting input minus output N in agro-ecosystem. However, a recent approach on determining N balance has been evaluated regarding a change in soil N stock for continuing crop cultivation. To describe an assessment method on N balance, this study was conducted with three different methods, Method A (Input N - Output N (crop N removal+Loss N) = N surplus or deficit), Method B (Input N - Output N (crop N removal+Loss N + Δ soil total N) = N surplus or deficit), and Method C (Input N - Output N (crop N removal+Loss N) + Δ soil total N = N surplus or deficit). Four levels (0, 60, 120, and 180 kg N ha<SUP>-1</SUP>) of N from urea and two levels (120 and 180 kg ha<SUP>-1</SUP>) of N from combination of urea and CM (Urea:Cattle Manure = 60:60 and 60:120) were applied in a lowland paddy soil. Results showed that Method B indicated all negative N values regardless the sources and rates of N application, while Method A and C described different N balance values in the given N applications. Using Method A, a response of N balance to urea applications (0, 60, 120, and 180 kg N ha<SUP>-1</SUP>) was linearly increased. The values of N balance were negative at 0 and 60 kg N ha<SUP>-1</SUP>, while it was close to zero at 120 kg N ha<SUP>-1</SUP> and showed the higher value at 180 kg N ha<SUP>-1</SUP>, respectively. Similarly, the combined N applications at 120 and 180 kg N ha<SUP>-1</SUP> showed similar N balance values. Meanwhile, Method C indicated different N balance values at the combined N applications, showing significantly higher N balance values at 120 kg N ha<SUP>-1</SUP> and the more value at 180 kg N ha<SUP>-1</SUP>, as compared with Method A. The difference was attributed to the soil N stock considering as count factor in determination of N balance. Thus, the study recommended Method C when evaluating both of soil fertility and N loading in crop cultivation field.